1. Field of the Invention
The present invention relates to a spectroscope and a spectrum laser microscope for detecting and analyzing spectra from a sample, in particular, to a spectroscope and a spectrum laser microscope capable of correcting fluctuation in sensitivity of each detector of a multi-channel photodetector.
2. Related Background Art
In the field of biology and medical science, study on intracellular communication is eagerly going on. In this area, a fluorescent microscope is used for exploiting characteristics thereof capable of selectively visualizing functional molecules (such as protein, inorganic substance, and the like) smaller than a cell, and observing interaction between a plurality of functional molecules, in addition to being able to dynamically observe living things alive in an almost natural state (including sufficient moisture in the atmosphere). Among the fluorescent microscopes, a fluorescent confocal laser microscope has recently been getting popular because of being able to obtain a cross-sectional imaging and a high contrast imaging. Fluorescence is emitted from a sample having a specific wavelength range in accordance with various states and conditions such as a kind of a fluorescence agent, a combined state between the fluorescence agent and the sample, and wavelength to be excited. In other words, existence, a state, and reaction of a material in the sample is confirmed from the wavelength of the fluorescence and its quantitative evaluation becomes possible by its intensity.
In order to find out phenomena occurring within a living body by strictly defining substance by analyzing fluorescence into spectra, a laser microscope has recently been proposed, in which the wavelength range of the spectra can be detected at a time by using a multi-channel photodetector constructed by a plurality of photodetectors (which are called as channels). To obtain spectra by this kind of a laser microscope is superior to a fluorescent microscope for detecting a single wavelength such that fluorescence spectrum information of the sample can be obtained visually as a two-dimensional image (for example, see National Stage Patent Application Translated Version Publication No. P2004-506192A).
However, in a laser microscope disclosed in National Stage Patent Application Translated Version Publication No. P2004-506192A, the multi-channel photodetector for detecting spectra (each photodetector (hereinafter called a channel) of anode type PMT (Photo Multiplier Tube) with such as 32 channels) does not have uniform sensitivity (according to quantum efficiency and a multiplication factor) and minute intensity of the spectra of the fluorescence cannot be obtained with required precision upon varying voltage applying to the multi-channel photodetector, so that it is a problem that strictly defining substance is difficult.